When developing I always try to use as few design elements as possible. It's a thing of mine, although surely not uncommon?

Last week I needed to do some server-side validation. First I wanted to validate in "real time" using Ajax to give the user feedback as they filled out the form and then, second, I wanted to validate again when the form was submitted (you should always validate on save).

I did something I'd never done before and which saved adding two new elements to do the same job; I used an Agent that works out whether it's being called directly via a URL call or whether it's being ran as part of the form's WQS event.

Here's How

It works in Java or LotusScript, but here's the concept as seen in Java:

import java.io.PrintWriter;
import lotus.domino.*;

public class JavaAgent extends AgentBase {

    public void NotesMain() {

        try {
            Session session = getSession();
            AgentContext agentContext = session.getAgentContext();
            Document docContext = agentContext.getDocumentContext();
            PrintWriter out = getAgentOutput();

            //Run code common to both agent calls here. 
            
            if (docContext.getItemValueString("Query_String").toLowerCase().indexOf("openagent")==0){
                //Run code specific to Ajax calls (and return some JSON)
                out.println("content-type: text/plain");
                out.println("{\"valid\":true}");
            } else { 
                //Run code only needed for WQS
                docContext.replaceItemValue("Valid", "1");
            }


        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

As you can see it works out if it's an Ajax call or not based on the Query String. Yes, even agents ran directly via the URL have a document context!

As it's a WQS agent it needs to be set to run on no documents and from the agent list. You can have your Ajax call the agent directly using the bracketed notation like this:

http://www.codestore.net/user.nsf/(ValidateCellNumber)?OpenAgent

You can also run the same agent in the Form's WQS:

One less Agent to maintain!

At some point I'll include this trick in a working Cell Phone Validator demo I plan on building in to Dext.

Gotcha

It's not perfect, as it relies on the agent being called with it's full formal URL of ?OpenAgent and not just a simple ?Open. But hey, that's a trade-off I'm willing to make.